1. Field of the Invention
The present invention relates to a digital camera system having an interchangeable lens and a camera body to which the interchangeable lens can be attached.
2. Related Art Statement
An image pickup device in a recent digital camera has a narrow dynamic range. Furthermore, it is difficult to receive and performs photoelectric conversion on light emitted diagonally at a predetermined angle or larger. Therefore, the influence of the decrease in amount of peripheral light is more significant than a silver halide camera. In order to solve the problem, Japanese Unexamined Patent Application Publication No. 6-37289 discloses a technology for increasing an opening diameter of a micro-lens on the periphery of an image pickup device. According to the disclosed technology, the opening diameter of a micro-lens of an image pickup device is increased continuously toward the periphery.
In order to reduce the influence of the decrease in amount of peripheral light, Japanese Unexamined Patent Application Publication No. 5-130469 discloses a technology for forming a light path of an image pickup device such that the vignetting of a light beam can be prevented in a light path from a photographic lens to the image pickup device. A video camera disclosed in the patent document has a larger opening in an image frame plate so as to prevent vignetting, and the strength of the image frame plate in a diagonal direction of the opening is reinforced by a projection.
On the other hand, a lens interchangeable, single-lens reflex type digital camera system has been disclosed. For example, an electronic camera disclosed in Japanese Unexamined Patent Application Publication No. 11-88783 relates to a single-lens reflex type electronic camera having a solid-state imaging device such as a CCD in a film opening by using the body of a conventional silver halide camera.